Johnson & Johnson’s Single Shot COVID-19 Vaccine Helps Monkeys

Johnson & Johnson recently announced that its lead COVID-19 vaccine candidate protected against SARS-CoV-2 infection in pre-clinical studies using monkeys.

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The data, published in Nature, showed that the candidate, Ad26-S.PP, had an immune response among rhesus macaques as demonstrated by neutralizing antibodies. This prevented future infection and provided complete protection in the lungs from the virus in non-human primates.

“We are excited to see these pre-clinical data because they show our SARS-CoV-2 vaccine candidate generated a strong antibody response and provided protection with a single dose,” Paul Stoffels, MD, vice chairman of the executive committee and chief scientific officer, Johnson & Johnson, said in the announcement. 

“The findings give us confidence as we progress our vaccine development and upscale manufacturing in parallel, having initiated a Phase 1/2a trial in July with the intention to move into a Phase 3 trial in September.”

Out of seven vaccine prototypes tested in the study, Ad26.COV2.S showed the highest levels of neutralizing antibodies to SARS-CoV-2. 

Specifically, there were RBD-specific binding antibodies in 31 of 32 vaccinated animals by week two and in all vaccinated animals by week four. Robust neutralizing antibodies responses were also found after a single immunization, which provided complete protection against SARS-CoV-2 in five of six animals. 

“A single-shot SARS-CoV-2 vaccine would have important logistic and practical advantages compared with a two-dose vaccine for mass vaccination campaigns and pandemic control. However, we would expect that a two-dose vaccine with Ad26-S.PP would be more immunogenic,” researchers said in the study.

The pre-clinical study was conducted by researchers from Beth Israel Deaconess Medical Center (BIDMC) in collaboration with Janssen Pharmaceutical Companies.

Dan Barouch, MD, PhD, director of the center for virology and vaccine research at BIDMC and the Ragon Institute, noted that the pre-clinical data suggests that antibody levels may serve as a biomarker for vaccine-medicated protection.

Fifty-two of the rhesus macaques in the studieswere immunized with Ad26-S.PP. They received a single immunization of 1011 viral particles Ad26 vectors by the intramuscular route without adjuvant at week zero.

Researchers then challenged them with SARS-CoV-2 infection. 

Based on the positive data, a Phase 1/2a first-in-human clinical trial of Ad26.COV2.S in healthy volunteers was launched in the US and Belgium.

The Janssen COVID-19 clinical trial program, including the Phase 1/2a clinical trial and the Phase 3 clinical trial program, will evaluate both one and two-dose regimens of Ad26.COV2.S in parallel studies, said Johnson & Johnson officials. 

The Phase 1/2a trial will evaluate the safety, reactogenicity, and immunogenicity of Ad26.COV2.S in over 1,000 healthy adults aged 18 to 55 years, as well as adults aged 65 years and older. 

A pivotal Phase 3 clinical development program of the single vaccine dose versus placebo may be initiated this September. The trial is contingent upon results from the Phase 1 and 2 trials.

Johnson & Johnson noted that it will focus on representing populations that have been disproportionately impacted by the pandemic in the US, including Blacks, Hispanic/Latinx, and individuals over 65 years of age.

“As we collectively battle this pandemic, we remain deeply committed to our goal of providing a safe and effective vaccine to the world. Our pre-clinical results give us reason to be optimistic as we initiate our first-in-human clinical trial, and we are excited to enter the next stage in our research and development toward a COVID-19 vaccine,” said Mathai Mammen, MD, PhD, global head, Janssen Research & Development, LLC, Johnson & Johnson. 

“We know that, if successful, this vaccine can be rapidly developed, produced on a large scale and delivered around the world.”